Revert "Test on PG15 beta (#2386)"

This reverts commit 39fa68d.

.github/workflows/build.yml

@@ -26,14 +26,15 @@ jobs:
         os: [ ubuntu-20.04 ]
         pg_major: [ 14, 13, 12, 11, 10 ]
         config: [Release]
+# PostgreSQL 14 is out, but there's no PostGIS binary for Windows yet (http://download.osgeo.org/postgis/windows/)
         include:
           - os: ubuntu-20.04
             pg_major: 14
             config: Debug
-          - os: ubuntu-20.04
-            pg_major: 15
-            config: Release
-            pg_prerelease: 'PG Prerelease'
+#          - os: ubuntu-20.04
+#            pg_major: 15
+#            config: Release
+#            pg_prerelease: 'PG Prerelease'
 
     outputs:
       is_release: ${{ steps.analyze_tag.outputs.is_release }}
@@ -57,7 +58,7 @@ jobs:
           dpkg-query -W --showformat='${Package}\n' 'postgresql-*' | xargs sudo dpkg -P postgresql
 
           wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
-          sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ focal-pgdg main 15" >> /etc/apt/sources.list.d/pgdg.list'
+          sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ focal-pgdg main 14" >> /etc/apt/sources.list.d/pgdg.list'
           sudo apt-get update -qq
           sudo apt-get install -qq postgresql-${{ matrix.pg_major  }}